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EXPLOSIVES: THEIR MANUFACTURE, PROPERTIES, TESTS, AND HISTORY. Arthur Marshall, A.C.G.I., F.I.C., F.C.S., Chemical Inspector, Indian Ordnance Department. Philadelphia, P. Blakiston's Son & Co., 1915. 605 pages and indexes. 8vo. Price, $7.

Few works of a purely technical character could just now attract more general attention, but it is not of any popular interest that this review should speak. The work is by an expert and represents a needed addition to the literature of an extensive and important department of applied chemistry. The attention of people at large is usually directed to the use of explosives for destructive purposes, but those familiar with the subject know that by far the more important use is in constructive operations, in which, at most, the destruction is only preliminary to improvement.

The work is comprehensive, including many details of the manufacture of the materials used in the making of explosives, as well as the process of manufacture of all leading types. Considerable attention is given to the theoretical side of the science, and a summary of the history of the development of explosives as used in war. In the latter we find, as might be expected, that some of the "Tales of our Grandfathers" are without basis, notably the story that the Chinese used gunpowder at a very early date. Mr. Marshall, however, shows that they did use potassium nitrate about the middle of the eighteenth century. The legend as to the great antiquity of Chinese gunpowder seems to have been due to mistranslations-depending on misunderstandings-by the Jesuit missionaries. Roger Bacon knew methods of preparing explosives with charcoal, sulphur, and saltpetre. Incidentally, Mr. Marshall's summary shows the truth of the current saying that gunpowder was invented by a monk and the percussion cap by a minister.

On taking up the book the reviewer was reminded of the opening lines of Macaulay's review of Nares's "Life of Lord Burghley," in which are given the volume and weight of the book. Mr. Marshall's book is no vade mecum. It has a volume of about two litres and weighs over two kilos. Bulk and weight are due largely to the use throughout of heavy surfaced paper, a procedure that the reviewer thinks might easily have been avoided.

A short article on fireworks is included, but no mention is made of photographic flash-powders. It seems to the reviewer that these deserve considerable attention. They are extensively used, many forms have been prepared, and much destruction of life and property has been occasioned by them. In Philadelphia alone nearly a dozen deaths have been caused by the mixtures. A good account of preparations now offered by leading firms should certainly be included in a work of such comprehensive character as this.

A great disappointment is the neglect of the modern standard nomenclature of chemical compounds. It is surely time that such terms as "chlorate of potash," "acetate of lime," and "chloride of sodium" should be avoided in a scientific work.

A paragraph of much present interest to American readers is the notice of the Louisiana sulphur mines. The deposits are at such a depth as to render ordinary mining methods too expensive, but by an ingenious use of high steam the sulphur is brought to the surface and collected. The perfection of the method is due to Hermann Frasch. Until these mines were opened the world's supply of free sulphur was almost entirely from Italy, but several hundred

thousand tons are produced each year in Louisiana, and the United States has not only enough for itself, but exports such large amounts that the Sicilian mines became unprofitable. The Italian Government has taken over the operation of these, and Mr. Marshall states that the present condition of the workers is better than ever before. HENRY LEFFMANN.

SPENCER FULLERTON BAIRD, A BIOGRAPHY, INCLUDING SELECTIONS FROM HIS CORRESPONDENCE WITH AUDUBON, AGASSIZ, DANA AND OTHERS. By William Healey Dall, A.M., D.Sc. Philadelphia, J. B. Lippincott Company, 1915. 450 pages, 19 illustrations. 8vo. Price, $3.50.

The subject of this work was the second secretary of the Smithsonian Institution, and organizer and first commissioner of the United States Commission of Fish and Fisheries. He died at Wood's Hole.

The data were largely collected by his daughter, Miss Lucy Hunter Baird, and to Dr. Dall was committed the task of selecting, arranging, and preparing them for publication. The forepart of the book contains a summary of the genealogy, and some incidents of the early life. The childish traits and early experiences of those who have become great are always of interest, and usually exemplify the truth of the adage that "truth is stranger than fiction." Perhaps the vividness of such recital is better preserved in an autobiography, if the editors have not used the blue pencil freely.

The letters that pass between distinguished men and women of similar tastes throw much light on the development and methods of human thought, yet it seems probable that, except in the case of those who have profoundly modified the general course of human events, comparatively few care to read the collection. By founding the Commission of Fish and Fisheries, Baird did much greater service to mankind than Peary did by reaching the Pole, or Roosevelt by shooting game in Africa and South America, yet thousands of people know of the exploits of the two latter for one who knows the service of the former. HENRY LEFFMANN.

PUBLICATIONS RECEIVED.

Test Methods for Steam Power Plants: A Reference Book for the Use of Power-station Engineers, Superintendents and Chemists, by Edward H. Tenney, B.A., M.E. 224 pages, illustrations, 12m0. New York, D. Van Nostrand Company, 1915. Price, $2.50 net.

Theatres: Their Safety from Fire and Panic, Their Comfort and Healthfulness, by Dr. William Paul Gerhard, C.E. Second edition, 110 pages, 12m0. New York, The Baker and Taylor Company, 1915.

Canada Mines Department, Mines Branch: Petroleum and Natural Gas Resources of Canada, vol. i, by Frederick G. Clapp and others. 378 pages, illustrations, plates, tables, maps, 8vo. Ottawa, Government Printing Bureau, 1914.

Michigan State Board of Health: Forty-first Annual Report of the Secretary for the fiscal year ending June 30, 1913. 183 pages, illustrations, 8vo. Lansing, State Printers, 1914.

A Text-book of Dispersoidology: Modern Colloidal Chemistry, by A. Janek. (In the Russian language.) 248 pages, illustrations, portraits, plates, 8vo. Petrograd, 1915.

U. S. Department of Agriculture: Farmers' Bulletin No. 657, The Chinch Bug, by F. M. Webster, in charge of cereal and forage insect investigations. 28 pages, illustrations, 8vo. No. 664, Strawberry Growing in the South, by H. C. Thompson, horticulturist, Office of Horticultural and Pomological Investigations. 20 pages, illustrations, 8vo. Washington, Government Printing Office, 1915.

Pennsylvania Topographic and Geologic Survey: Report No. 2, Geologic Map of Southwestern Pennsylvania. 29 pages, maps, 8vo. No. 8A, The Mineral Production of Pennsylvania, 1911, Coal and Coke. 139 pages, 8vo. No. 8C, Clay and Clay Products, 1911. 51 pages, 8vo. No. 8E, Quarry Products, Granite, Trap Rock, Sandstone, Bluestone, Marble, Limestone, Lime. 84 pages, 8vo. Harrisburg, Telegraph Printing Company, 1915.

U. S. Bureau of Mines: Technical Paper 88, Mineral Technology 6, The Radium-uranium Ratio in Carnotites, by S. C. Lind and C. F. Whittemore, 29 pages, 8vo. Technical Paper 95, Mining and Milling of Lead and Zinc Ores in the Wisconsin District, Wisconsin, by Clarence A. Wright. 39 pages, illustrations, 8vo. Technical Paper 101, Permissible Explosion-proof Electric Motors for Mines; Conditions and Requirements for Test and Approval, by H. H. Clark. 17 pages, illustrations, 8vo. Monthly Statement of Coal-mine Fatalities in the United States, March, 1915, compiled by Albert H. Fay. 12 pages, 8vo. Washington, Government Printing Office, 1915.

Calculation of Illumination with Indirect or Semi-indirect Light Sources. RICHARD C. POWELL. (Electrical World, vol. 65, No. 23, 1463.)-Calculation from the photometric curve and height of a source of light is a well-known and commonly-used method for predetermining the distribution and intensity of illumination from a direct light source. But when indirect or semi-indirect units are employed, the usual course is to rely upon judgment or a preliminary test which often is not convenient. In the method of calculation developed it is necessary to know only the photometric curve, the coefficient of reflection for the secondary source (usually the ceiling), the distance of the unit below the ceiling, and the height of the ceiling above the plane of illumination. While this method is not so simple as in the case of direct units, still it is believed to be sufficiently so to make it of considerable value to those planning lighting installations.

Outline of Method. The light unit produces on the ceiling a secondary light source in the form of a circular disk, generally of non-uniform intensity. This disk may, however, be considered as made up of a number of circular annuli or rings of uniform intensity of illumination. The effect may also be considered the same as that which would be produced by a number of uniformlyilluminated concentric disks of varying radii. By calculating each disk separately and adding the results there is obtained approximately the illumination due to the ceiling. By taking a sufficiently large number of disks we may make the approximation as close as desired, but in practice it is usually sufficient to take four.

CURRENT TOPICS.

Production and Shipments of Portland Cement, 1914.-Figures gathered by United States Geological Survey show decrease in both quantity and value of output. The total production of Portland cement in the United States in 1914, according to Ernest F. Burchard, of the United States Geological Survey, was 88,230,170 barrels, valued at $81,789,368; the production for 1913 was 92,097,131 barrels, valued at $92,557,617. The output for 1914 represents a decrease in quantity of 3,866,961 barrels, and a decrease in value of $10,768,249. The value assigned to the production is computed on the basis of 92.7 cents a barrel, or the average value of the Portland cement shipped in 1914.

The shipments of Portland cement from the mills in the United States in 1914 amounted to 86,437,956 barrels, valued at $80,118,475, compared with 88,689,377 barrels, valued at $89,106,975, shipped in 1913. This represents a decrease in quantity of 2,251,421 barrels, and in value of $8,988,500. The average factory price per barrel in bulk for the whole country in 1914 was 92.7 cents, compared with $1.005 in 1913, a decrease of 7.8 cents a barrel. This price is about. 11.8 cents higher than the average price in the Lehigh District and is near the average price in New York, Illinois, Iowa, the Southeastern States, and the Plains States, but falls 42.5 cents below the average price received in Utah, where Portland cement brought the highest figure during the year.

Among the States there were unimportant changes in rank as cement producers. Pennsylvania and Indiana held first and second places respectively, as for many years, but both of these large cementproducing States suffered an appreciable reduction of output. In 1913 the output of California exceeded that of New York and Illinois, but in 1914 this State dropped from third to fifth place. New Jersey dropped from seventh to ninth place, having been passed by both Michigan and Iowa in 1914. The State of Kansas, which has attracted considerable attention in the cement world, first because of the rapid development of the industry within its borders on account of the proximity of abundant supplies of suitable raw material and cheap natural gas, and later because of the waning of the gas supply and the consequent increase in cost of manufacture of cement which resulted in curtailment of output, maintained its rank of tenth among cement producers and suffered but little reduction of output, although the price of cement here fell considerably below the average. Iowa and Ohio both showed gratifying increase in output and appear also to have kept prices up more successfully than many other States. In the Far West, in Washington, conditions were brought into better balance by a considerable curtailment of production and an increase

in shipments, although prices fell heavily; in Utah production was largely and shipments slightly increased, and prices were also increased. The only other States showing increase of prices were New Jersey and Texas.

Of the twelve commercial districts into which the United States is divided, there was an increase in production in five-New York, Michigan-northeastern Indiana, Maryland-West Virginia, IowaMissouri, and the Rocky Mountain States-and an increase in shipments in seven-New York, Ohio-western Pennsylvania, Michigan-northeastern Indiana, Kentucky-southern Indiana, MarylandVirginia-West Virginia, Iowa-Missouri, and the Rocky Mountain States. There were decreases in production in seven districts— Lehigh, Ohio-western Pennsylvania, Kentucky-southern Indiana, Illinois-northwestern Indiana, Tennessee-Alabama-Georgia, Great Plains, and Pacific coast-and decreases in shipments in five districts-Lehigh, Illinois-northwestern Indiana, Tennessee-AlabamaGeorgia, Great Plains, and Pacific coast. The largest percentage of increase of production was reported from New York, but the increase in shipments in that district was only half as great. The districts that showed the heaviest percentages of decrease in both production and shipments were the Tennessee-Alabama-Georgia district and the Pacific coast.

Production of Pyrite and Sulphuric Acid in 1914.-The production of pyrite in the United States in 1914, according to W. C. Phalen, of the United States Geological Survey, was 336,662 long tons, valued at $1,283,346. In 1913 the production was 341,338 long tons, valued at $1,286,084. There was a decrease, therefore, in 1914 of 4676 long tons in quantity, or slightly more than one per cent., and of $2738 in value, or but one-fifth of one per cent.

Virginia is the leading State in both production and value. The output of this State diminished slightly in 1914 as compared with 1913. The output in California showed a slight gain. There was a substantial gain in the production in New York, which, though ranking third among the States in production, stands second in value. In Illinois, where pyrite is a by-product obtained in connection with coal mining, the output more than doubled compared with 1913. In Wisconsin there was a decreased production. In Georgia there was a slight increase. In both Ohio and Missouri there was a decline in production, and in Indiana, where, as in Illinois and Ohio, the pyrite is obtained in connection with coal mining, there was a slight increase as compared with 1913.

Imports of Pyrite.-The imports of pyrite for consumption during the calendar year 1914 were 1,026,617 long tons, valued at $4,797,326. These figures show a notable increase compared with the imports of 1913, which were 850,592 long tons, valued at $3,611,137. The increase in imports in 1914 amounted to 176,025 long tons, and in value to $1,186,189.